A Study on Supplementation of Non-Fat Yoghurt with Psyllium

Abstract

ABSTRACT Skim buffalo’s milk supplemented with psyllium husks (PSH) or seeds (PSS) was used for making stirred yoghurt. Milk was heated at 90oC /10 min and quickly cooled to 42oC (control, without psyllium) and to 60oC for supplementation with PSH at ratios of 0.5, 1.0 and 1.5%, w/v (A1, A2 and A3) and with PSS at ratios of 0.5, 1.0 and 1.5% w/v (B1, B2 and B3) and then cooled (42oC) to be ready for fermentation. The resultant yoghurt was analyzed when fresh and during cold storage (4oC) for 7 and 15 days for chemical, physiochemical and sensory properties. The obtained results for the different treatments with psyllium indicated almost significant increase (P≤0.05) on total solids, total protein and ash content. Generally, titratable acidity gradually increased through storage period and pH decreased with different rates due to type and amount of supplement. PSH and PSS enhanced formation of acetaldehyde and increased carbohydrate at different storage periods and  subsequently increaseD the energy of the treated yoghurt. Water holding capacity and viscosity were almost significantly increased by supplement and by amount of both PSH and PSS and with advancing storage period. The control yoghurt had the lowest values of both of them. Organoleptically, the use of PSH or PSS at level of 1.5% (w/v) gave improved body and texture without any adverse impact on the flavour of the prepared product.